" Models are used as substitutes for originals because properties of the latter are of interest and the originals are not going to be investigated themselves. There may be a number of reasons for that such as taboos preventing from studying the original itself, or inability, the involved cost in terms of resources or moral damage being intolerable, or similar . For an investigator I it makes only sense to consider an entity M as a substitute of an entity O, if I can (1) establish an analogy, similarity, or similar relation between M and O that permits the substitution of O by M with respect to purpose and means, time-horizon etc. , and (2) I can actually investigate M in the required way. That implies firstly that M does not have the properties of O that prevent I from investigating O. Also other properties of O may not be properties of M. In that sense a model is more abstract than its original. Barbara Model Portfolio Secondly, a model M will in general have properties that O does not have and that actually aid I in investigating M. What the investigator I does in modeling is formulating a problem P in terms of the original O, translate that problem into a problem P' in terms of M, obtain a solution S' of P' and translate S' into a solution candidate S of P in terms of O. "

" References Textbooks Griffiths, David J. (1987) Introduction to Elementary Particles, Wiley, John & Sons, Inc. ISBN 0471603864 Journal Articles Y. Hayato et al. , Search for Proton Decay through p → νK+ in a Large Water Cherenkov Detector. Phys. Rev. Free Online Model Portfolio Lett. 83, 1529 (1999). "